Aproveitamento agroindustrial de cactáceas do semiárido brasileiro.

Abstract

The present work had as an objective to develop alimentary products: juice and sliced bread with the incorporation of “facheiro’s” fruits and “mandacaru”. The study was divided in four chapters. In the First Chapter, the processing of fruits and the quantifying of the industrial yielding of the pulp, rind, and seed took place. The chemical and physical-chemical characteristics of the pulps and rinds of the fruits of “facheiro” and “mandacaru” were determined. In Chapter 2, the pulps of the fruits of “facheiro” and “mandacaru” were frozen with the objective of determining the kinetic, at the temperatures of -25 °C, in a freezer, then at -60 and -150 °C on cryogenic counter and by their immersion in liquid nitrogen -196 °C. In Chapter 3 it was obtained the powder of the pulp of the fruits of “facheiro” and “mandacaru” through the process of freeze-drying, where it was studied the effect of the freezing subjugated to the pulp at three freezing temperatures -25 °C, -60, and -150 °C. During the freeze-drying process it were determined the kinetics of the drying, where the mathematics models of Cavalcanti Mata, Midilli, Kucuk &Yapar, Page and the exponential of two terms were utilized to predict the behavior of the drying curve. The freeze-drying material got in powder form was subject to chemical and physical-chemical analysis. The powdered pulp of the fruits of “facheiro” and “mandacaru”, frozen-dried at the freezing temperatures of -25, -60, and -150 °C were subject of sensorial analysis. In Chapter 4, the optimization of the convective drying of the fruit’s rind took place by applying the experimental factorial planning studying the influence of the temperature (T) and the velocity of air (var) during the drying. The mathematics models of Cavalcanti Mata, Midilli, Kucuk &Yapar, Page and the exponential of two terms were utilized to predict the behavior of the drying curve. The dried material obtained in powder form was submitted to chemical and physical-chemical analysis. Sliced bread was utilized by substituting 10% of the wheat flour for flour made out of the rind of the fruits of “facheiro” and “mandacaru” in the different drying temperatures (50, 60 and 70 °C) for sensorial analysis. Based on the results obtained it was verified that the “facheiro’s” pulp yielded less than the pulp of “mandacaru”. Their pulps demonstrated contents of soluble solids, ascorbic acid, reducing sugars, total sugars, and higher caloric values than the rips of the fruits. The freezing time was less in the fruit of “mandacaru” rather than the pulp of the fruit of “facheiro”, for the temperatures of -25, -60, -150, and -196 °C. The freezing curves of the pulp of the fruits were -25, -60, -150, and -196 °C happen in less time as the freezing temperature decreases. The effective thermal diffusivity of the pulps of the fruits of “mandacaru” and “facheiro” is directly proportional to the increase of the gradient of the temperature and the inverse to the tenor of the water at the temperatures of -25, -60, -150, and -196 °C. The mathematical model of Cavalcanti Mata, in a general way is the one who best predicts the kinetic of the drying by the freeze-drying process. It was verified that the decrease of the freezing temperature gathered a higher freeze-drying time, both to the pulps of “facheiro” and “mandacaru”. It was found through sensorial analysis that there were no significant differences between the samples of juices studied and that there was no influence of the freezing temperature. The entering variables: temperature and the velocity of the air on the drying significantly influenced under the response variables. The empiric model of the second order was the one who obtained the highest statistical significance values. The mathematic method proposed by Cavalcanti Mata is the model that best predicts the drying behavior of the rids of the fruits of “facheiro” and “mandacaru”.